The present embodiments relate to sub-aperture control for high intensity focused ultrasound (HIFU) therapy.
HIFU is used for non-invasive tumor ablation or homeostasis. Uterine fibroids, various bone metastasis, liver, kidney, pancreas, and breast cancers may be treated. Other possible treatments using HIFU include homeostasis of liver and blood vessels.
HIFU may be applied from within the patient, such as using an intracavitary applicator, but these devices are invasive and only applicable to specific organs. Extracorporeal HIFU devices are non-invasive. Existing extracorporeal HIFU devices are typically bowl shaped and contains a limited number of elements. Multiple element HIFU devices have been approved for uterine fibroid treatment. Some extracorporeal HIFU devices may lack flexibility in aperture size and focal depths. One example extracorporeal HIFU device has a 26 cm aperture, consisting of 251 PZT elements with electronic control of the small changes in focus position and mechanical positioning for large changes of the focus position. Another example extracorporeal HIFU device has a 12 cm spherically curved single element mechanically positioned for all focus position and depth adjustments. Another HIFU device contains less than 1000 elements. Typically, the elements are driven with individual phase control to achieve focusing and steering. Some extracorporeal HIFU devices may lack flexibility in aperture size and focal depths.